Perfluorooctanoic Acid (PFOA) and Human Health: A Position
Paper of the American Council on Science and Health

Concern has been raised about possible human health effects of perfluorooctanoic
acid (PFOA) and related compounds, which have been detected in human blood
in many locations. Evidence suggests that these compounds are persistent
in the environment and human body. Studies of laboratory animals indicate
that high doses can result in liver and kidney toxicity, and developmental
and carcinogenic effects. However, the compounds do not appear to be mutagens.
From mechanistic considerations, the relevance to humans of at least some
effects seen in animals is questionable. Toxicities observed in animals
have not been seen in worker populations. Comparisons of both blood levels
and drinking water exposures of PFOA in the general population to levels
associated with adverse effects in laboratory animals demonstrate that
a margin of safety of hundreds to thousands exists. Thus, current data
indicate that risk to the general population from PFOA and related compounds
is quite low.

Life Cycle Methodology for Assessing Sustainable Growth
of Energy Resources

Ryuji Matsuhashi,1 Eiki Ohashi,1
and Hisashi Ishitani2

1Institute of Environmental Studies, Graduate School of Frontier
Sciences, and 2Department of Geosystem Engineering, Graduate
School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan

Sequestration of CO2 is expected to be an effective option
for mitigating climate change. This article aims at clarifying role of
CO2 sequestration in global energy scenarios. For this purpose,
the concept of "sustainable limits" on depletable resources and CO2
emissions is proposed. Based on this concept, energy resources and CO2
emissions require the introduction of measures such as CO2 sequestration
or photovoltaic systems. Consequently, life cycle performances of CO2
sequestration and photovoltaic systems were evaluated. Input-output analysis
was applied to develop life cycle inventories of the evaluated systems,
and life cycle CO2 emissions and energy requirements of these
technologies were quantitatively estimated. Based on the life cycle inventories,
economic condition of each estimated technology with and without carbon
tax was identified. The evaluated results showed the intrinsic difference
between CO2 sequestration and renewable energy technologies.
At the same time, they indicated how the economic incentives influence
cost-effectiveness of the measures. Based on the results of this study
it can be concluded that CO2 sequestration could play a transitional
but significant role to realize sustainable energy systems.

Assessment of Temperature Changes in Various States
of the United States

Sorin R. Straja

Institute for Regulatory Science, Columbia, MD 21045, USA

This article is the first of a larger study to evaluate regional temperature
changes and attempt to draw conclusion on potential global temperature
change. This aticle evaluates whether two states from the US have experienced
a significant long-term temperature change. The two states chosen for this
study are Alabama and North Dakota. Alabama was chosen because it is a
southern state, while North Dakota was chosen as the state with the reputation
to be the coldest state within the contiguous 48 states of the US. The
data collected do not support the hypothesis of a significant temperature
change. However, the sample size is relatively small with respect to the
sampling frequency. For the North Dakota stations 322188 (Dickinson Experimental
Station), 324178 (Hettinger) and 326315 (New England), although a significant
temperature change was not detected, further analysis is necessary to understand
the nature of the deterministic signals detected by the Lomb periodogram.

Given the operational constraints of aerospace ground equipments (AGE),
nonthermal plasma discharge (NTPD) has been identified as a promising technology
for their NOx removal. As part of a program to optimize an NTPD
system for this particular application, an investigation of the effect
of discharge gap spacing and other factors on the electrical and chemical
processes that occur in NTPDs was initiated. A number of experiments were
performed to examine how the gap spacing affects the NO removal efficiency,
discharge characteristics, and chemical reactions in a NTPD device. Optimum
gap spacing and other conditions for NO removal were observed based on
the experimental data and modeling. A physical explanation for the optimum
was developed. The experiments, numerical approach, results, and conclusions
are discussed in detail in this article.

When released into the atmosphere, the group of compounds collectively
known as nitrogen oxides (NOx) contributes to photochemical
smog, acid rain, and ground-level ozone. Combustion processes are a primary
source of NOxemissions and finding a cost-effective technology
to remove NOx from combustion exhaust streams is essential.
Given the operational constraints of aerospace ground equipment (AGE),
nonthermal plasma discharge (NTPD) has been identified as a promising technology
for NOx removal. As part of a program to optimize an NTPD system
for this particular application, an investigation of the affect of discharge
gap spacing on the electrical and chemical processes that occur in NTPDs
was initiated. A number of experiments were performed to examine how the
gap spacing affects the NOx removal efficiency, discharge characteristics,
and chemical reactions in a NTPD device. Gap spacings ranging from 0.8
to 4.0 mm were considered in this study. An optimum gap spacing for NOx
removal was observed at approximately 2 mm and, based on the experimental
data, a physical explanation for the optimum was developed. The experiments,
the results, and conclusions are discussed in detail in this article.

Physical and chemical parameters were measured in the water body and
in 442 seawater samples collected over a period of 6-11 months in 1998
from 13 nearshore stations along the coastline of Kuwait, including Al-Shuwaikh
coast. Despite the marked regional and seasonal variations recorded in
the properties of the seawater under study, all average values of the physical
and chemical parameters, particularly nutrients, total petroleum hydrocarbons,
and trace metals, are far below the concentration limit (CL) set for seawater
and drinking water quality by local and international regulating bodies,
emphasizing the good quality of the coastal waters in Kuwait at the present
time. Values recorded for the physical and chemical properties of Al-Shuwaikh
seawater are more or less similar to those recorded for Kuwaiti coastal
waters and the northern Gulf waters and are all within the CLs set by local
and international standards for the quality of seawater and/or drinking
water, verifying the good quality of Al-Shuwaikh seawater during the whole
period of 1998. Results obtained from the analysis of mercury in 102 water
samples collected from 51 stations offshore Al-Shuwaikh coast emphasized
that the mercury content of all samples is quite low and far below the
CL of this pollutant, and hence the seawater in Al-Shuwaikh coastal area
(including the area under study) can be regarded as currently unpolluted
with mercury.

Mercury analyses made on 249 surface and core sediment subsamples collected
in 1998 have revealed that the silty bottom sediments in the southeastern
nearshore area of the former Salt and Chlorine Plant (present Oil Sector
Complex) along Al-Shuwaikh coast are currently contaminated with mercury,
while the bottom sediments of the nearby Power and Desalination Plant nearshore
area and the northern seaward area have low mercury content. The presence
of high and intermediate concentrations of the element (from 2.7 to 17.5
mg/g), the weak nearshore current, and the low
energy depositional regime in the southeastern nearshore area all suggest
that the silt sediment column (~50 cm deep) beneath the sea floor in this
limited marine area (20,000 m2) has acted as a sink for the
mercury effluents dumped into Al-Shuwaikh coastal water via the outfalls
of the chlorine plant during its production activity from 1964 to 1984.
Any disturbance of the mercury-contaminated silt sediments (~10,000 m3)
during offshore construction activity or due to accidental damage of the
complex as a result of unforeseen military operations and/or seismic activities
would lead to the upward migration of the mercury. Therefore, it appears
prudent to remove completely the contaminated areas of marine silt and
replace them with clean material before starting any construction activity
in the study area.

New data on the spatial distribution of trace metals in inter-tidal
flat sediments in 10 sampling stations, which were clustered into four
variable zones of the upper New Calabar River in Port Harcourt, Nigeria,
are presented. The flame atomic absorption spectrophotometric technique
was used for all metal determination. Much higher concentrations were detected
near most likely anthropogenic sources of trace metals inputs, which may
be ascribed to petroleum refinery, industrial, and domestic effluents discharged
into the river from a number of outfalls within the zones. Trace metals
in these contaminated intertidal sediment cluster zones were up to 0.95
mg g-1 for Hg, 38.30 mg
g-1 for Ni, 17.75 mg g-1
for Co, 27.35 mg g-1 for Cu, 201.30
mg g-1 for Cr, 3.60 mg
g-1 for Cd, 265.65 mg g-1
for Mn, 131.15 mg g-1 for Pb, and
136.25 mg g-1 for Zn. Cluster analysis
of distribution pattern and of available tidal hydraulic data indicates
that the metal concentrations are due to a combination of sources and tidal
hydraulics. All metals except Hg form strong correlation (p <
0.05) with the sediment organic carbon, indicative of sediment as an adsorptive
sink. Comparison of trace metal levels in intertidal flat sediments of
the upper New Calabar River and sediments of rivers from other geographical
regions indicates that the upper segments of the New Calabar River intertidal
flat sediments have elevated levels of trace metals, but have not been
grossly contaminated.

Leaf samples from 16 plants were collected from selected roads in parts
of the Niger Delta region of Nigeria and analyzed for lead using the dithizone
colorimetric method. The results show that lead concentrations in samples
from the high traffic density areas were significantly (p < 0.05)
higher than lead concentrations in samples from low traffic density areas
and a positive correlation (r = 0.9162) exists between them. Lead concentrations
in the leaves decreased with increasing distance from the road (r
= -0.8579). Lead levels in the dry season samples were higher than the
wet season samples but the difference between them was not statistically
significant (p > 0.05). The lead levels found in the high traffic
density areas exceeded threshold limits. Farming activities along major
traffic roads are discouraged because the concentration of lead in the
environment is increasing.